Definitely 18mm ply-- apart from the obvious stability problems of 12 mm ply there is also the problem of the tee nuts sticking out on the climbing side. Flexing panels will need more structural work behind and stronger anchors to the supporting structure- it simply isn't worth the hassle. Don't even think about MDF!

Remember to batten out the ply from any solid way (so over long bolts can stick out at the back).

I strongly advise you to use small (12mm) screws to double fix any tee nuts from behind especially if you don't have easy access. It is very easy to lose tee nuts otherwise.

Budget for lots of tee nuts - I make ~70 per 8*4 ply board.

You should reinforce any anchors you use (eg bolt hangers) for belaying. Even if you don't intend to belay on the wall consider a line of bolts to the top if the top is out of easy reach (makes route setting easier).

As for holds you can manufacture a lot yourself from offcuts of ply - they work really well - you can texture with grip paint or sand and glue (get kiln dried sand or use a water soluble glue - PVA is ok but very slow to dry).

As others have pretty much implied, MDF is definitely not the way to go.Use 18mm ply or even sterling board/similar if you're on a tight budget.

Bolt length will depend on the size of the holds you're planning on using. For the minimal price difference, 50mm is a better for your 'average length' required, although I've got some holds on my board that needed 100 or 120mm bolts.

Holds: just search the usual manufacturers' sites or even your local wall. You'll usually find something suitable.

Get a mixture of bolt lengths and head styles - holds come in different thicknesses! Make sure you can check the bolt length can be accomodated behind, it is easy to jack you climbing wall off the support if your bolts are too long...

This thread was started in the ROCKTALK forum and has now been moved.
Please could you try and post in the correct forum, it makes life easier for both users and moderators.

Walls & Training - Find out where the best climbing wall is in your area. Who goes there? What are the facilities like? Build your own cellar. Training tips and injuries info. It's all here. (And don't forget to check the Classified Listings which contain the UK's most comprehensive online database of climbing walls.)

As others have said, definitley not MDF. I used 18 mm ply and it has been spot on. 35 mm bolts fine for most holds but i do have some bought holds that need 50mm as they are deeper. As someone else has said offcuts of ply or any other wood can make great holds especailly for footholds where the 'feel' is irrelevant(especially if wall is very steep - mine is about 35 degree overhanging)You can still use your bolts to attach wooden holds and so they are just as interchangeable into any other T nut as all of your others. Good luck with it.

Joe - if you need a hand putting it up, let me know. I think Paul is putting up a board as well, so you might get some help off him. If you have a space, the moon board looks awesome. Just buy a good selection of holds. You'll end up resettings stuff a fair bit anyway.

In reply to joe gallacher: I followed the moon board PDF. But I changed the angle to 30 degrees and it was a bit smaller to fit the garage. Frame is 2by4 inches rough sawn pine. With 3/4 inch 19mm in metric red top ply. I use core and bleaustone holds from rock and run, excellent choice and service. Ask them about what holds would suit what you want to achieve and they'll advise you. Bolts, as someone said you need the size that fits the hold. Most of mine protrude about 20-30mm from the back of the hold.

Mine is hopefully going up next month, aiming for a 30 to 35 degree overhang but will probably make it adjustable. Given the height of my garage I should be able to make the wall 2.8m in length, any thoughts on if that's big enough to bother with? At a 40degree angle I could stretch it to 3m or so.

In reply to misterb: I imagine it can't be much more boring than a fingerboard which is the only thing my garage is used for right now. It's mostly just somewhere to go, pop on a bit of music and do a bit of climbing related exercise when I can't get out.

In reply to joe gallacher: Mines 18mm playwood attached to a freestanding scaffold frame, seems to work quite well, i wouldnt buy many hold get a load of wood and get cutting and sanding wood is more friendly to train on and doesent shred the skin.

In reply to peewee2008: Thanks peewee , my DIY skills will ensure there is plenty of wood left over for holds.........and bolts left over ...and nuts !! plus the bits that I won't remember where they came from etc etc , cheers joe

In reply to joe gallacher: hi Joe, above notes are great, 18mm ply, I used araldite on the tnuts to keep them in place, its a 2 part glue. As for holds, buy some resin online with catalyst, mix with 30% sand. Make moulds from plastercine by pressing stones into them, grease the bolt and put that in the required place and fill with your resin and sand mixture. I used fine shot blast sand. Alternatively... Make your own holds from foam or stick with stones and use liquid latex to make reusable moulds.

In reply to Kieran_John: mine is 8ft wide what that is in metric I have no idea. It's 9 foot in length. I have a endurance lap around the perimeter of the board. It's 18 moves long, with the 30 degree over hang it takes a lot out of me to lap it twice. Pushing to 3 laps. It is more fun than a fingerboard. Especially when there's a few of you. Just have to do a good warm up before hand.

In reply to Kieran_John:
Same here - putting up a wall in the garage (pretty much 8x8x8 feet area to work in) in the coming weeks/months, probably at 35 degrees. Tips on here have been useful, thanks! Would be interested to see people's constructions once they're complete.

Bouldering wall in world's smallest garage! Proved tough getting it all set up due to the angle/weight . I bought the board pre-made/bolted from someone on here which is why it's a little shorter on the top right.

Made up a couple of circuits on it today, it's big enough for what I need it for and it's certainly more fun than staring at a wall using my finger board.

In reply to Kieran_John:
Good job, looks nice - definitely more interesting than a finger board I've got the wood for mine, drilled the boards and t-nutted them so far, but can't build it until some work's done to the house in a couple of weeks. Will stick a couple of pics up when it's done as well.